Somebody mentioned the Fedex pilot. What was to stop him carrying out an attack when he was operating if he had been denied the opportunity to use the jumpseat?
Unfortunately life occasionally carries some risk (ssshhh! don't tell the personal injury lawyers).
These new rules will achieve absolutely nothing and if a terrorist wants to blowup/crash another aircraft he/she WILL find a way to do it. If that remote possibility is an unacceptable risk to anybody then why not stay at home and put on another layer of cotton wool.
These rather sad new regulations are just another example of bureaucracy replacing commonsense, a seemingly contagious condition spreading amongst the misnamed 'developed' nations.